1. Field of the Invention
The present invention relates to the field of modular storage and transport mechanisms for storage of many CDs: CD-ROM; CD-I; CD-ROM XA; MMCD; KODAK PHOTO CD; VIDEO DISCs (to be named from this point on known as Multi Session) and selective data access and/or recording of a plurality of discs simultaneously.
2. Background and the Prior Art
As the volume of data grows exponentially in the business world with the introduction of huge on-line databases, electronic document storage, fiber optic subscriber links, multimedia presentation software, multi-tasking machines running complex programs in multiple windows, a need has arisen for mass storage devices which can store multiple megabytes of data with fast access time.
In addition, the music CD has enjoyed ever increasing popularity since its invention in 1982. Consumers have developed large collections of CDs and a need has developed for a means to store them and play them back into a music system.
Likewise, the CD-ROM mass data storage media for computers has also started to increase in popularity and is expected to increase in popularity as a teaching and management of mass information media using complex graphic and video presentations, which, by virtue of the need for storage of huge quantities of data, virtually require CD-ROM storage media.
Optical read-write discs are rising in popularity because of the capacity to store vast quantities of data. Video discs are also available as an alternative media to video tape, and some consumers have large collections thereof. In addition, software programs are becoming larger and larger, and it is expected that software manufacturers will with increasing regularity begin delivering their software on optical discs to save on media and mailing costs.
In more sophisticated systems such as networks where large quantities of data and programs are stored on distributed servers, it is expected that servers will eventually make use of read-write optical discs because of the increased data storage capacity thereof.
Because of this evolution of storage media, there has arisen a need for secure, large volume storage of these valuable optical discs, and a need for easy, nondestructive and automated access to selected ones thereof for playback for data retrieval/recording and data storage. Various systems exist in the prior art for storage and playback of music CDs and CD-ROMs. Examples of the types of prior art systems in existence now include:
CDworks family of machines (Model 1000) by Virtual Microsystems of San Mateo, Calif.: A CD-ROM based server for network applications. Apparently only a single CD-ROM is resident although the literature is unclear on this; PA1 NSM HiFI Visions CD Player and Dual CD Magazine: Two 50 CD magazines with CDs stacked in vertical arrays with CDs horizontally oriented. A shuttle moves vertically to the selected CD and removes it with its protective tray and then delivers the CD to a player; PA1 Sony CDK-3600 Auto Disc Loader: Handles storage, loading and playback of up to 360 compact discs. Dual CD players are built in. A computer may be connected to the unit via an RS-232 port for automated control of the playback process. Up to 28 units may be daisy chained to control up to 9,999 CDs. Disc access time is less than 2 seconds with disc loading time less than 15 seconds; PA1 Boffin CD-ROM Mini Tower: A 4 bay CD-ROM tower with 4 CD-ROM drives. Used for large database operations. PA1 Corel SCSI for Jukeboxes: Supports all WORM discs, which may be rewritten and multi-function optical disc jukeboxes by interfacing the jukebox with a network via a NetWare 386 file server thereby allowing the jukebox to be seen on the network through a standard Novell volume that has been defined on the file server's hard disc; PA1 Denon DN-1200F 200 CD Changer: Access to 200 CDs with access time between discs of approximately 12 seconds. This unit can cascade up to 16 CD changers on a single serial port. Dual 100 disc magazines store 200 CDs in two linear arrays. Details of the transport system and player mechanism are unclear; PA1 Sony 100 CD Disc Changer for music CDs: Up to 100 music CDs may be stored in a circular vertically oriented array. Details of the disc transport and player mechanisms are unclear. The CDs may be grouped into different categories electronically; PA1 Fisher Studio 24 CD Management System: Stores and organizes up to 24 music CDs in a circular vertically oriented array. Two units can be connected in tandem to access up to 48 discs. Teaches a single vertical slot for loading of CDs; PA1 U.S. Pat. No. 4,519,055, filed Apr. 19, 1983: Teaches a doughnut shaped cartridge storage module, a changer or transport mechanism and a record/read station. The storage modules is a carousel type with radially cartridge storage modules that can store up to 100 CDs. A changer mechanism resides in the center and rotates about a center axis, but has a different structure than taught in the invention; PA1 U.S. Pat. No. 2,839,305 teaches a selective record changer with a carousel of vertically stored records with a central player and a transport mechanism which selects the record out of the array and moves it to the player.
3. The Problem with the Prior Art Approaches
None of the prior art approaches have as fast an access time as is possible. Generally speaking, the prior art approaches involve a transport mechanism with a geometry which requires the selected disc to move farther than is necessary in order to reach the playback position. Typically, the disc must be removed from the storage area to a playback position by the transport mechanism requiring several degrees of freedom in motion.
Another problem with the prior art is expansion. As collections of music CDs, CD-ROM discs and data storing optical read-write discs grow larger, prior art systems become too small and must be replaced by bigger, more expensive systems for storage and playback.
Prior art storage and transport mechanisms are generally limited to storage and playback of only one type of optical disc. Thus, a storage and playback mechanism for music CDs cannot retrieve data from CD-ROMs and supply it to a computer.
Therefore, a need has arisen for a storage and transport mechanism which can store large numbers of optical discs and which can adapt to an ever-growing collection size without being rendered obsolete. The system should enjoy fast access time and have the ability to store and playback any type of optical disc of the same general diameter regardless of the data type stored thereon. Further, the system should be capable of accessing a plurality of disc for simultaneous playback and/or recording.